Vaccine Therapy, Cyclophosphamide, and Cetuximab in Treating Patients With Metastatic or Locally Advanced Pancreatic Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed ductal adenocarcinoma of the pancreas * Mixed adenocarcinoma tumors eligible provided the predominant invasive component of the tumor is adenocarcinoma * The following histologic diagnoses are not eligible: * Adenosquamous * Squamous cell * Colloid * Islet cell * Serous or mucinous cystadenoma or cystadenocarcinoma * Carcinoid * Small or large cell carcinoma * Intraductal oncocytic papillary neoplasms * Osteoclast-like giant cell tumors * Acinar cell carcinoma * Pancreatoblastoma * Solid pseudopapillary tumors * Undifferentiated small cell carcinoma * Nonepithelial tumors (sarcoma, gastrointestinal stromal tumor, lymphoma) * Adenocarcinomas of the ampulla, distal bile duct, or duodenum * Metastatic or locally advanced disease that is refractory to standard therapy OR for which patient refused standard therapy * Measurable disease defined as ≥ 1 lesion unidimensionally measured as ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT scan * No nonmeasurable disease only including, but not limited to, the following: * Bone lesions * Leptomeningeal disease * Ascites * Pleural or pericardial effusion * Inflammatory breast disease * Lymphangitis cutis/pulmonis * Abdominal masses that are not confirmed and followed by imaging techniques * Cystic lesions * No known active or untreated brain metastases PATIENT CHARACTERISTICS: * ECOG performance status 0-1 * WBC ≥ 3,500/mm\^3 * Absolute neutrophil count ≥ 1,500/mm\^3 * Hemoglobin ≥ 9 g/dL * Platelet count ≥ 90,000/mm\^3 * Creatinine ≤ 2.0 mg/dL * Bilirubin ≤ 2 mg/dL * ALT and AST ≤ 5 times upper limit of normal (ULN) * Alkaline phosphatase ≤ 5 times ULN * No active infection * No uncontrolled medical condition that would potentially increase the risk of toxicities or complications of study therapy * No gastrointestinal tract disease resulting in an inability to take oral medication or a requirement for IV alimentation * No active peptic ulcer disease * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for 4 weeks after completion of study treatment * No other malignancy within the past 5 years except for nonmelanomatous skin cancer, superficial bladder cancer, or carcinoma in situ of the cervix * HIV negative * No active autoimmune disease or prior autoimmune disease requiring medical treatment with systemic immunosuppressants including any of the following: * Inflammatory bowel disease * Systemic vasculitis * Scleroderma * Psoriasis * Multiple sclerosis * Hemolytic anemia or immune thrombocytopenia * Rheumatoid arthritis * Systemic lupus erythematosus * Sjögren's syndrome * Sarcoidosis * Asthma or chronic obstructive pulmonary disease that does not require systemic corticosteroids or routine use of inhaled steroids allowed * No known or suspected hypersensitivity to sargramostim (GM-CSF), cyclophosphamide, pentastarch, corn, or DMSO * No prior severe infusion reaction (\> grade 3) to a monoclonal antibody PRIOR CONCURRENT THERAPY: * See Disease Characteristics * More than 1 month since prior adjuvant chemotherapy * More than 4 weeks since prior surgery except for minor procedures (e.g., dental work, skin biopsy) and biliary stent placement * No prior surgical procedures affecting absorption * More than 4 weeks since prior radiotherapy * More than 1 month since prior participation in an investigational new drug study * No unresolved chronic toxicity (except alopecia) from prior anticancer therapy * More than 28 days since prior systemic steroids * No concurrent systemic steroids or immunosuppressive drugs * Topical, inhaled, and intra-articular steroids allowed * No other concurrent anticancer vaccine therapy * No other concurrent chemotherapy, immunotherapy, radiotherapy, gene therapy, biologic therapy, or investigational therapy